The present invention pertains to collated fasteners. More particularly, the present invention pertains to a collated nail strip formed with a scalloped-edge tape, for use in a fastener driving tool.
Fast-acting fastener driving tools are in widespread use in the construction industry. For use in these tools, the nails are assembled in strips that are inserted into a magazine of the tool. The strips are flat and the nails or other fasteners are held parallel to one another. The nails are assembled in a staggered or stepped manner such that the major axis of the nail forms an angle to the longitudinal direction of the strip. In presently known collated nails, the angle is about 10 degrees to 40 degrees and preferably between 15 degrees and 25 degrees. An in-depth discussion of such fasteners is provided in U.S. Pat. No. 5,733,085, to Shida, which is incorporated herein by reference.
Presently known collated nails are assembled using tape strips or an extruded plastic material. The plastic (or polymer) in the plastic-formed strips is cooled and hardens to hold the nails in the strip form for use in the tool. The tape strips are formed from a kraft paper or other paperboard material having a plastic (polymer) adhesive on a surface thereof that is heated on contact with hot nails and, as it cools, adheres to the nails.
The tape strips have the advantage of minimizing the debris that is formed as the tool is actuated and the nails are driven into the material (typically wood) to be fastened. However, with the tape strip it has been observed that the strip can flex and tend to advance on each other. This is a condition known as corrugation and has been found to be one of the greatest causes of tool jamming and fastener failure, and increases as the nails are spaced farther apart.
One way in which the corrugation problem has been addressed was to use a thicker tape with a relatively large quantity of adhesive material on the tape (to secure to the nails). However, it was found that as the strip's resistance to corrugation increased, the force required to separate the nail from the strip and to shear the tape, e.g., resistance to shear, increased as well. As such, nails tended to remain affixed to the tape and jamming of the tool occurred.
Accordingly, there is a need for a paper tape collation system for strip-formed fasteners that reduces the tendency for the nail strip to corrugate in the tool magazine. Desirably, such a system reduces the tendency to corrugate without increasing the shear required to properly separate the nail from the strip in a predetermined manner as the tool is actuated. More desirably, such a system reduces the tendency to corrugate without substantially increasing the size of the tape or the amount of adhesive.